Elvanol 75-15

1. Mechanism of Elvanol in Paper Surface Treatment In the modern paper industry, surface treatment has become an important means of increasing the added value of paper. Printability, surface strength, and barrier properties against oils and solvents all highly depend on the material selection of the surface sizing or coating system. Elvanol polyvinyl alcohol, as a high-performance water-based film-forming material, is widely used in paper surface treatment.     Elvanol is a fully or highly hydrolyzed polyvinyl alcohol with excellent film-forming ability. Its regular molecular chain structure allows it to form a continuous and dense film during drying, significantly improving the surface strength and barrier properties of the paper. Compared to using starch alone, the film formed by Elvanol is tougher, has stronger chemical resistance to oils, waxes, and solvents, and exhibits higher water resistance.   Using Elvanol in the sizing press or calendering stage can significantly improve the paper's resistance to linting, dusting, and cracking. Even at low addition levels (approximately 10% solids content), it can achieve surface strength and folding strength superior to traditional starch systems. This characteristic makes it particularly suitable for high-filler paper, recycled fiber paper, and paper types requiring high printability.   In addition, Elvanol has good compatibility and can coexist stably with modified starch, CMC, alginates, wax emulsions, and common papermaking additives, providing greater flexibility for papermaking process adjustments.   2. Application Advantages of Elvanol in Improving Barrier, Strength, and Printing Performance ♣ Surface Barrier Properties Elvanol is one of the most powerful water-based barrier film-forming materials in the paper industry. The film it forms has a natural barrier effect against oils, greases, and organic solvents, and is therefore often used in applications such as greaseproof paper, oil-resistant packaging paper, and copier paper. In oil-resistant systems, Elvanol can also serve as an effective carrier for fluorochemicals, improving the stability and efficiency of the overall barrier system.   ♣ Surface Strength and Structural Stability Compared to starch-sized paper, paper treated with Elvanol exhibits superior resistance to surface abrasion, cracking, and linting. Its high bonding strength effectively binds fibers and fine surface particles, reducing linting and dusting, thereby lowering the frequency of blanket contamination and downtime for cleaning during printing. This advantage is particularly evident in high-speed offset printing and high-precision printing. At the same time, Elvanol allows for a higher proportion of fillers or recycled fibers while maintaining strength, helping paper mills control costs while maintaining paper performance.   ♣  Printability and Coating Suitability Elvanol-treated paper surfaces are smoother and have excellent ink holdout. Due to its oil and solvent resistance, ink does not easily penetrate the paper base, resulting in higher print gloss and image clarity. In pigment sizing systems, Elvanol, as a binder, exhibits significantly stronger binding power than acrylic emulsions, styrene-butadiene latex, casein, and starch, and can replace traditional binders at certain ratios, optimizing the pigment/binder ratio.   3. Typical Elvanol Grades and Application Characteristics in Papermaking Based on different paper types and process requirements, we offer a variety of product grades with different viscosities and structures. The following are commonly used grades in the papermaking industry and their application characteristics: Grade Polymer Type Viscosity Level Key Functions Typical Uses Elvanol 71-30 Fully hydrolyzed PVOH Medium Film forming, binding, grease resistance Surface sizing; FWA carrier; lint and dust control; grease-resistant papers Elvanol 80-18 Fully hydrolyzed PVOH Medium Grease barrier, high solids stability Grease-proof packaging papers; high-solids sizing and coating Elvanol 75-15 Fully hydrolyzed PVOH Medium–Low Binder reinforcement Starch reinforcement; lint reduction; high-solids sizing and coating   In optical brightening systems, Elvanol acts as a carrier for fluorescent whitening agents (FWAs), significantly improving whitening efficiency. Adding Elvanol at 0.5–2.5% of the pigment weight in pigment systems results in significantly better whitening effects than using FWA alone, while also reducing the amount of traditional carriers such as starch and casein.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Polyvinyl alcohol (PVA) is a water-soluble synthetic polymer with excellent film-forming properties, surface activity, and strong adhesion to inorganic and cellulosic materials. Global annual PVA production is approximately 1.05 million tons, with Japan producing approximately 300,000 tons. Approximately 14,100 tons of this is used as a paper processing chemical, a surface sizing agent for plain paper, a sizing agent for coated and coated paper, a fluorescent brightener, an inkjet ink absorber, an adhesive for inorganic fillers, and a silicone sealant for release paper.   The paper business faces challenges like using different types of wood pulp and faster, bigger machines for making paper and printing. Because of this, they need better water-soluble polymers with special features. These polymers are important for making fancy specialty papers and papers used in tech. To adapt to these fundamental changes in the papermaking industry, Kuraray Japan has developed and mastered the properties of modified PVA with novel properties. This article will focus on two specialty PVA: the silanol-modified "R-series PVA" and the high-barrier "Exceval PVA" with the introduction of special hydrophobic groups. The two types will be discussed, along with their properties and applications in paper processing additives.   2. PVA Properties and Dissolution Methods Industrially, PVA is produced by polymerizing and then saponifying polyvinyl acetate. Its fundamental properties depend on its degree of polymerization and saponification. Most commercially available PVAs had a degree of polymerization of 200 to 4000 and a degree of saponification of 30% to 99.9% by mole fraction. The main varieties of PVA produced by Kuraray (Kuraray PVA) are shown in Tables 1 and 2.   3. Specialty Kuraray PVA To date, Kuraray has produced a variety of Kuraray PVAs with varying degrees of polymerization and saponification, which are used in a wide range of applications. As demand grows for better PVA and more varied uses, just tweaking the polymerization and saponification degrees isn't enough anymore. So, Kuraray PVA now comes with special groups added to give it extra function.   This article will introduce two types of functionalized PVA: the "R-series PVA," modified with silanol groups, and the "Exceval PVA (Exceval HR-3010)," which incorporates special hydrophobic groups for high barrier properties.   3.1 Silanol-Modified R-series PVA The R-series is a modified PVA with silanol groups. Table 3 lists the quality standards for the R-series products.     3.2 High Barrier Exceval PVA Exceval PVA is a PVA containing special hydrophobic groups. The introduction of hydrophobic groups enhances the crystallinity of the solid polymer, resolving the dilemma of achieving both high water resistance and stable aqueous solution viscosity, which is difficult to achieve with standard PVA. The use of PVA is increasing annually. PVA is usually used as a stabilizer in adhesives that need to resist water. But, when used in food packaging films, PVA doesn't block oxygen well when it's humid. Exceval PVA is also being developed as an improved material. In coated paper applications, Exceval PVA has also been successfully used when higher water resistance than PVA is required.   This article reports on the results of a new application study for Exceval PVA, specifically its use as an oil-resistant agent in food packaging. The product specifications of the Exceval PVA used in this study are shown in Table 4.   Table 5 shows that coating with Exceval PVA RS-2117 achieves air resistance roughly equivalent to that achieved with partially saponified PVA-217, while significantly reducing water absorption. Paper coated with partially saponified PVA exhibits higher air resistance. This is because the highly hydrophobic, partially saponified PVA has a lower surface tension in aqueous solution, inhibiting penetration into the paper. However, partially saponified PVA suffers from a significant reduction in water resistance. While Exceval PVA, modified with a special hydrophobic group, is fully saponified, it still exhibits the same permeability as partially saponified PVA, offering both improved water resistance and air impermeability.   R-series PVA contains highly reactive silanol groups, which improve adhesion to various inorganic materials. Using the R-series in inkjet media reduces the amount of polyvinyl alcohol used as a binder for silica particles, improving print quality. Even without a crosslinker, the R-series provides high water resistance. Exceval PVA is a modified, hydrophobic polyvinyl alcohol that offers excellent water resistance and gas barrier properties under high humidity conditions. The lower air permeability of coated paper provides a higher barrier to oils and greases than fully water-soluble polyvinyl alcohol, a property further enhanced when used with flake minerals. Exceval is now FDA-registered as safe for contact with food, opening doors for its use in food packaging paper.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com